In early 2002, when the John Madden-Pat Summerall team called its final N.F.L. game together, they celebrated and reminisced about a 21-season partnership that began at CBS and ended at Fox. Madden was off to ABC’s “Monday Night Football” and Summerall stayed at Fox for one more full season.

The end of Jon Miller and Joe Morgan’s 21-season run on ESPN’s “Sunday Night Baseball” came Monday, more than a month after their final televised game. There was no news release or tribute to them, just Norby Williamson, an ESPN executive vice president, talking to a few reporters.

It was time for a change, he said, time for new perspective, yet time to appreciate Miller and Morgan’s contributions to building the “Sunday Night” franchise. Still, in conveying its appreciation, ESPN was saying that Morgan was no longer welcome, but if Miller wants to shift to radio, he’s aces.

If it’s any consolation to Morgan, he stuck around longer than the FireJoeMorgan.com Web site.

For some, Morgan’s end is a time to celebrate. He became cranky, often intransigent, frequently humorless and a grim listen — the Grumpy Old Analyst. I’ve always felt that he was, even at his best, too impervious to Miller’s lightheartedness, that he just didn’t get his partner’s wit.

Morgan issued a terse response that was far from an “I want to thank ESPN for the opportunity” statement. “I was not surprised by ESPN’s decision,” he said. “They have been taking ‘Sunday Night Baseball’ in a different direction the last two years, and I was not comfortable with that direction.”

Without elaboration, we are left to believe that Morgan disliked sharing the booth with a second analyst: Steve Phillips in 2009 and Orel Hershiser, who replaced Phillips, in 2010.

“It’s a dramatic change in the direction and structure of the booth,” Phillips said in a telephone interview Thursday. “After 19 years, it’s understandable that he felt that way. A third man changes the flow, the rhythm and the topics; it could not have been subtle change for him.”

But Phillips said Morgan did not air his frustrations to him.

“And if he listened to outside criticism about him, I don’t think he cared about it,” Phillips added.

ESPN waited until Miller and Morgan’s contracts were up to make the change; soon enough, it will announce that Dan Shulman and Bobby Valentine will join Hershiser for 2011 and beyond.

But ESPN did not make its decision based on the anti-Morgan howls from critics, bloggers and fans. It waited years to react. Why it felt a need to dispatch Miller, too, is a mystery. But in parting ways with him, it did not ultimately matter that less than four months ago, he had taken his place among other honored voices in the Baseball Hall of Fame. Just bad timing on the road to change.

Or maybe it was the day off Miller took from calling a game to accept the Ford C. Frick Award on induction Sunday in Cooperstown that cinched ESPN’s decision.

James Andrew Miller, a co-author of the forthcoming book “Those Guys Have All the Fun: Inside the World of ESPN,” said in an interview that the Bristol empire had often stuck with announcers in the face of criticism and replaced them on its own timetable.

“It wasn’t like the criticism of Joe started last week, and they decided to pull the plug,” Miller said. “They hung in for quite some time with him.” He added: “But ESPN is not afraid to make changes. Ask Joe Theismann. Ask Tony Kornheiser. Ask Mike Patrick.”

Theismann and Patrick lasted a long time on “Sunday Night Football.” When ESPN swapped Sunday nights for Monday nights, it substituted Mike Tirico for Patrick. Theismann joined Tirico for a season on “Monday Night Football” until Theismann was traded in for Ron Jaworksi. Kornheiser, an unconventional choice whom ESPN was very happy with, lasted three seasons until a conventional option, Jon Gruden, took over.

Theismann and Kornheiser were the focus of considerable outside criticism for various reasons. But ESPN waited, moving the talent around on its own schedule.

Miller, the author, said he wondered, “What is the tipping point” that cues the start of musical chairs?

ESPN has chosen not to comment any further than Williamson did Monday.

Telling sportscasters that they are no longer wanted — or that it is time for a change — is not a simple task. Mel Allen never really got over being fired from the Yankees when he was just 51. As announcers head into their 60s, their errors sometimes mount, their eyesight falters and their preparation decreases. Yet some older announcers, like Vin Scully, Bob Uecker or the late Ernie Harwell, grow more beloved as they move into their 70s and 80s as icons of their franchises.

Jon Miller, 59, is the radio and TV voice of the San Francisco Giants. Morgan is 67, with various business interests including an advisory role with the Cincinnati Reds that began last season.

Networks march on. Shulman will be an excellent replacement for Miller. Hershiser showed himself quite capable last season, but Valentine’s loquaciousness might create a battle for airtime.

Who knows when Fox will decide to dismantle its lead baseball announcing team of Joe Buck, who is 41, and Tim McCarver, who is 69. Their time will almost certainly come. It’s called change.

E-mail: sandor@nytimes.com

A version of this article appears in print on November 12, 2010, on page B12 of the New York edition with the headline: ESPN Baseball’s Inevitable Change. Order Reprints|Today's Paper|Subscribe